Development and validation of an IA-LC/MS method to quantitate active and total B-type natriuretic peptide in human plasma.

Aim: Patients with elevated levels of B-type natriuretic peptide (BNP) and/or NT-proBNP as measured by clinical tests have an elevated risk of heart failure (HF). Despite utility in large clinical studies, both assays are plagued by large biological variability and specificity issues. To address these concerns and further investigate BNP in the HF setting, we developed an LC/MS assay to characterize the ratio of active to total BNP.

An evaluation of an aptamer for use as an affinity reagent with MS: PCSK9 as an example protein.

Background: For quantitative immunoaffinity IA-LC-MS, the utility of antibodies has been demonstrated many times but the utility of aptamers as affinity reagents is unproven.

Methods: Immunoaffinity reagents including a monoclonal antibody and an aptamer were coupled to magnetic beads and used as part of an enrichment strategy for PCSK9 quantitation in plasma.

Results: With limited method development, we have established a comparison of an anti-PCSK9 aptamer with an anti-PCSK9 monoclonal antibody.

An ultrasensitive method for the quantitation of active and inactive GLP-1 in human plasma via immunoaffinity LC-MS/MS.

Background: Measuring endogenous levels of incretin hormones, like GLP-1, is critical in the development of antidiabetic compounds. However, the assays used to measure these molecules often have analytical issues.

Results: We have developed an ultrasensitive, highly-selective immunoaffinity LC-MS/MS (IA LC-MS/MS) assay capable of quantitating endogenous levels of active (7-36 amide) and inactive (9-36 amide) GLP-1 in human plasma.